COM Object desactivated

[SAJMED]


Can Some body please explain to me why I can't have access to this Com object that I register zith regsvr32.

[hskoglund]

Hi, if you place the mouse cursor over the dimmed out "Dctl Control", i,e, here:

Qt Creator should display a grey box...

[hskoglund]

Re. why it's dimmed, perhaps you're running on a 64-bit Windows version?
If yes, then you have to do a regsvr32.exe twice, one for 32-bit registration and one for 64-bit registration, like this:

C:\Windows\SysWOW64\regsvr32.exe dctl.ocx
C:\Windows\System32\regsvr32.exe dctl.ocx

[SAJMED]

Thanks @hskoglund for the answer, I'am using 64-bit windows version And I registred the dctl.ocx as you showed me but it doesn't work

[hskoglund]

Perhaps you are using a 64-bit compiler for your Qt app? When dealing wuth these 15 to 20 years old OCX-files, your best bet is to use Qt 5 (not Qt6) and a 32-bit compiler like MSVC2019.

[SAJMED]

I'am using Qt 5.12 MinGw 64-bit, And I need to use it because I have other dlls that are only compatible with this version

[hskoglund]

5.12 MinGW is ok but I think for displaying OCX controls you have to use the 32-bit version of 5.12 MinGW :-(
(A common solution is to split your app into two apps, one for the 64-bit stuff and for the 32-bit OCX)

[hskoglund]

Hi again, googled a bit and verified that 32-bit OCX controls cannot be displayed/used from a 64-bit .exe file. So you have to split up you app somehow.

One way could be to keep as much as possible in your 64-bit app, and then build a 32-bit .exe Qt out-of-process ActiveX server (which just has a QMainWindow for showing the .OCX control.) For creating the ActiveX server you can use QAXContainer

Your ActiveX server would still have ti 32-bit to be able to host the dctl.ocx control, but because it's a standalone .exe server, you can communicate with it through QAxObject from your 64-bit main app :-)

[SAJMED]

Hi @hskoglund ! Thank you for helping me, I tried to use the 32-bit version of 5.12 MinGW to test but I'm still getting the ocx desactivated.

[SAJMED]

I tries again using the 32-bits version and I converted the OCX into .cpp and .h so as to integrated to Qt. And now it works :

#include "mainwindow.h"
#include <QApplication>
#include "ocx1lib.h"
#include <QDebug>
#include "combaseapi.h"

using namespace OCX1Lib;

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    Dctl readObj;
    readObj.SetEnabled(false);
    readObj.SetLinkTopic("ncdde|ncu840d");
    qDebug() << "LinkTopic : " << readObj.LinkTopic();
    readObj.SetLinkItem("/Channel/Parameter/R[15]");
    qDebug() << "LinkItem : " << readObj.LinkItem();

    readObj.SetData("7");
    readObj.SetEnabled(true);
    readObj.SetLinkCmd(CmdPoke);
   
    //MainWindow w;
    //w.show();
    //return a.exec();

    return 0;
}